A top economist fled Russia after being interrogated over the case of jailed oil tycoon Mikhail Khodorkovsky, amid fears that he could be targeted over a report saying that the ex-Yukos chief's conviction was unjust.
Sergei Guriyev, the dean of the New Economic School, is one of several experts who reviewed Khodorkovsky's case for the Kremlin's human rights council.
Based on the views of the team of experts, including Guriyev, the human rights council said that Khodorkovsky's second embezzlement and money laundering conviction was unjust.
It then recommended that investigators reconsider the controversial case against Khodorkovsky.
Guriyev's lawyer Ruslan Kozhura told AFP that his client was questioned by investigators in connection with the Yukos case more than a month ago.
The lawyer added that his client is a witness in the probe and has not been charged.
Guriyev, now in France, would only say that he was on vacation.
He said he was forbidden to talk about the Yukos case due to a confidentiality oath.
"I can only say that I did participate in the expert evaluation," he told AFP in emailed comments, adding he believed the report was conducted in an "ethical manner."
Khodorkovsky has been in jail since 2003 on fraud and tax evasion charges.
Shortly before his scheduled release, his stay in jail was extended during a second and controversial trial in 2010 in a move that drew strong condemnation from the West.